Dsup (contraction of damage suppressor) is a DNA-associating protein, unique to the tardigrade, that suppresses the occurrence of DNA breaks by radiation. When human HEK293 cells were engineered with Dsup proteins, they showed approximately 40% more tolerance against X-ray radiation. The Dsup protein has been tested on other animal cells. Using a culture of human cells that express the Dsup protein, it was found that after X-ray exposure the cells had fewer DNA breaks than control cells.